Engine Compression Specification

[flatch69]

Can anyone tell me what compression I should have in the cylinders on a TRX?

Today i measured it as 35psi and 55psi. I think this is way under spec.

More than likely the biggest reason it wont start too.

[cobbadiggabuddyblooo]

Check your valve clearances, this may be the culprit.
Just hope the inlets are not damaged. Is it a 95-96 model???

[dicky]

The service manual lists standard compression as 1,200kPa / 12Bar at 300rpm, which is approx 174psi

[lenny]

Did you do the compression check with a warm motor and the throttle wide open? I have seen people do a compression test with a closed throttle and wonder why the reading is low.

[flatch69]

Thanks for the feedback.

I repeated the compression test this morning wet/dry & throttle open/closed all on a cold engine as it wont start. I have attached the results below.

I then checked the valve clearances and found all the inlets are touching the cam. I could not even get a 0.05mm feeler gauge in between the cam and bucket.

I have a couple of questions if anyone could help?

1, Has anyone else seen similar readings on their bikes?
2, Is the lack of clearance on the inlet valve a sign of a larger problem with the valves and valve seats?
3, Is the 20psi increase between dry/wet compression tests enough to consider a deeper stip down investigating the rings and bore condition?

Thanks for the support.

[flatch69]

I sent the bike to my local repair shop. I just got the diagnosis.

A top end rebuild is required as all valves have "mushroomed" heads. Inlets are really bad. This is going to be an expensive fix.